Opening Paper

Sociocultural and Economic Functions of Acacia albida in West Africa

E.G. Bonkoungou¹

Abstract

Populations in Sudano-Sahelian Africa have developed agrosilvipastoral production systems in which trees and shrubs play a vital role in crop and animal production. Acacia albida is one of the most favored trees in such production systems. It is revered by the local people and is central to various popular myths and religious belief. The mythology of the Bambara people, for example, associates A. albida with the creation of the world. In the Dallor Maouri region of Niger, the species is part of the inheritance which the rural people pass on to their children. Yet, current research programs focus mainly on the biology of the species, leaving socioeconomic issues largely unexplored. This paper highlights the importance of some of the sociocultural and economic functions of A. albida in West Africa and argues that future development should focus more on socioeconomic research.

Introduction

Throughout the temperate countries, current practices allocate separate domains to agriculture, forestry, and animal production. For centuries, however, populations in Sudano-Sahelian Africa have developed and preserved an integrated agrosilvipastoral production system in which trees and shrubs play a vital role in crop production. According to Pélissier (1980), changes in African agriculture have not been accompanied by the elimination of the tree, but rather by its association with crops.

Agrarian lands of Sudano-Sahelian Africa are frequently associated with the following park types: Acacia albida, Butyrospermum paradoxum, subsp parkii/Parkia biglobosa, the "dim" tree (Cordyla pinnata), and "gum gardens" (Acacia Senegal). In certain cases, palm-tree formations dominate the tree stratum, e.g., the borassus palm (Borassus aethiopium), doum palm (Hyphaene thebaica), and, in oasis areas, the date palm (Phoenix dactylifera). For centuries, these traditional agroforestry systems have carried out important sociocultural and economic functions for populations that have, in turn, continually regenerated them. Unfortunately, agricultural research has been organized on a sectoral basis. The agronomists are focusing solely on crops in the field and the foresters on trees in a forest. This approach limits the potential role of trees in agriculture.

Today, the international scientific community, through the Consultative Group on International Agricultural Research (CGIAR), proposes expanding the organization in order to include optimal land management by integrating agriculture and forestry. Hence, the role that field trees play in the agricultural production and rural economy of Sudano-Sahelian rural farmers has been recently recognized by the scientific community. The current workshop on A. albida is an important contribution to this new agricultural research approach, since this is one of the principal tree species particularly favored by the rural farmer. The workshop is being held almost 30 years after the first research program on A. albida was initiated at the agronomic research station in Bambey, Senegal.

This paper will start the discussion by addressing research and development done on trees (particularly A. albida) in agrarian systems of Sudano-Sahelian Africa so as to pinpoint the current extent of knowledge on the species and to outline a few perspectives indicating the direction for future efforts.

Functions of Trees in Sudano-Sahelian Africa

In all times and in all civilizations, trees have been a subject of symbolic thought and have inspired myths and religions. In West Africa, numerous legends relate the founding of villages near large trees. L'arbre à palabre, a well-known meeting place in villages, is often a reminder of the founding ancestor and even sometimes shelters his grave. The tree has therefore been considered as a sacred intermediary between the living and their ancestors, and sometimes receives worship and offerings. Certain trees are said to be endowed with magical powers and move at night.

In addition to their important place in myth and religion, trees also serve an economic purpose that closely links them to man. Besides providing timber and firewood, trees furnish a great variety of non-woody products, some of which are sold on international markets: Butyrospermiwi paradoxum nuts, gum arabie, incense, and various resins. Numerous other nonexported products, as well, play a fundamental role in the diets and health of man and animals: fruits, flowers, leaves, bark, roots, tubers, sap, etc. In addition to being important to dietary balance in daily life, a number of these products are critical to the survival of entire populations during periods of food scarcity or famine. Considering the great importance of trees in the socioeconomic life, it is not surprising to see their full use in agricultural and food production strategies. They are not merely a curiosity for ethnologists or anthropologists, but rather a true economic factor affecting the great majority of populations of Sudano-Sahelian Africa, including city dwellers. These products, apart from being consumed at home, are also traded on local markets both in villages and in the towns.

For domestic animals and wildlife, forest and field trees represent rare sources of protein during the dry season. They provide a highly sought-after fodder, replacing the grasses, which diminish in quality and quantity during this period.

The long tradition of integrating trees into agrarian systems in Sudano-Sahelian Africa has unfortunately been limited to preserving existing trees. This has not evolved into directly regenerating trees on agricultural lands. With the exception of live hedges (generally propagated vegetatively), Sudano-Sahelian Africa has not developed a planting tradition comparable to that which gave rise to the huge olive orchards in the Mediterranean basin. Today, many tree stands in West Africa are being degraded by the combined effects of land pressure and drought, and the absence of a planting tradition constitutes, at least in part, a serious constraint to regenerating existing parks or establishing new ones.

Sociocultural and Economic Functions

The general functions of trees outlined above apply to A. albida to varying degrees, depending on the location. The functions of A. albida differ widely from one region to another within its vast natural distribution area, which covers the whole of semi-arid Africa, north and south of the equator.

In eastern and southern Africa for example, A. albida occurs with natural vegetation along temporary and permanent watercourses. Its integration into agrarian systems by traditional practice is unknown. Except for the use of its seeds, which are consumed in certain regions during times of famine, the socio-economic uses of A. albida are unknown as well. In West Africa, however, it is socially important. This is evident in cultural and religious life as well as in economic activities. The species is a mainspring of agrosilvipastoral production systems for many agrarian civilizations. This is largely due to its reverse phenology and its abundance in fields; field population density is considerably higher than those of natural stands in southern Africa.

Because of the unique benefits it confers and its strange phenological behavior, A. albida is often associated with divine powers. Man has sought to win favors of this divine power through worship and offerings and by reserving for A. albida a special place in myths and religious beliefs. The mythology of the Bambara people, for example, associates A. albida with the creation of the world. It is said that the initial mass that gave birth to the earth was then transformed into a seed of A. albida. Among the Dogon people, the elderly lie on a board of A. albida wood to extend their lives; corpses are carried on a stretcher made of its branches.

A. albida is also valued for its shade and quality fodder. A stand of this tree allows intensive farming without the need for a fallow period. Beneath this tree, crops, especially cereals, produce good harvests. Traditional practices integrating A. albida into the agricultural production system have been perfected by the Haussa of Niger (Giffard 1974), the Seres of Senegal (Pélissier 1966), the Bwaba of Burkina Faso (Savonnet 1959; Capron 1965), the Dogon of Mali (Gallais 1965), and diverse agrarian civilizations of the Niger River Delta (Gallais 1967). The importance of A. albida in the region of Zinder in Niger (circa 1860) was reflected in the sultan's decrees, which dictated: "he who cuts an A. albida tree without authorization will have his head severed; he who mutilates it without reason will have an arm cut off (Giffard 1974). The importance of this species is so well established in rural economies that, in dividing fields, certain ethnic groups take into account the number of A. albida trees.

Assessment of Past Studies

Modern science came to be interested in the agronomic merits of A. albida around 40 years ago, but experimental research on it did not start until 1966, at the Institut Sénégalais de recherches agricoles, in Bambey, Senegal. The following institutes participated:

• The Institut français de recherche scientifique pour le développement en coopération (ORSTOM) was in charge of studying soil microbiology beneath the tree and the nitrogen-fixing action of A. albida;

• The Institut de recherches agronomiques tropicales et des cultures vivrières (IRAT) studied the influence of the microclimate created by the tree as well as the effect of shade on soil and on crop yields;

• The Institut de recherches pour les huiles et olea-gineux (IRHO) focused on the impact of the species on groundnut development and pod yields; and

• The Centre technique forestier tropical (CTFT) studied traits of the wood and tree growth, and defined a planting technique for the species.

The results of this vast program were published by Charreau and Vidal (1965); Dancette and Poulain (1968); Jung (1969); Giffard (1974); and Felker (1978). The principal conclusions indicate important differences under and outside the cover of A. albida, notably in terms of soil, microclimate, and crop yields. For example:

• The percentages of total nitrogen and carbon are twice as high under A. albida than outside its cover;

• Biological activity is two to five times greater under A. albida than outside its cover;

• On lands where millet yields around 500 kg ha^-1, the yields approach 1000 kg ha^-1 at the limits of A. albida foliage and can attain 1700 kg ha^-1 near the boles.

Up to the present, these improvements were thought to be caused by the presence of A. albida; however, a recent hypothesis proposed by Vanden-beldt (1991, personal communication) suggests that it is rather the preexistence of favorable microsites on these different locations that facilitates establishment of A. albida (Geiger et al. 1992).

The end of the Bambey program was followed by a 10-year period during which interest in A. albida appeared to flag. Neither research nor development took new initiatives. Furthermore, the Bambey research remained solely technical and did not have any major impact on development projects.

It was after 1979 that scientific interest in A. albida revived, with the implementation of a project sponsored by the Food and Agriculture Organization of the United Nations (FAO), focusing on the genetic resources of several tree species. This project was not started specifically for A. albida, but it contributed to reviving scientific interest in this species (Bon-koungou 1985). Unlike the previous period which was particularly marked by a preoccupation explaining and quantifying the impact of A. albida on soil characteristics, microclimate, and crop yields, this new period—which is still current—is characterized by a concentration of research efforts on genetic resources and stock improvement. The principal activities are provenance comparison trials, vegetative propagation, symbiosis studies, and electrophoretic analyses of gene frequencies.

In addition to the FAO project, tree seed centers in Burkina Faso, Senegal, and Zimbabwe have advanced knowledge on A. albida (and other species) by identifying natural stands from which to collect seed, seed harvesting, and phenological monitoring. This new period has also been characterized by:

• a large diversification of funding sources, which include France, the International Development Research Centre (IDRC) of Canada, the European Economic Community (EEC), and the World Bank;

• the first implementation of a multi-institutional approach involving non-African [Oxford Forestry Institute (OFI) in the UK, CTFT and the Ecole nationale du genie rural des eaux et des forets (EN-GREF) in France] as well as African partners like the Institut de recherches en biologie et ecologie tropicale (IRBET) in Burkina Faso, the Institut Sénégalais de recherches agricoles (ISRA), and the University of Dakar in Senegal;

• the publication of two monographs (Bonkoungou 1987; CTFT 1988), which readily provide the scientific community and the public with information on the state of research on A. albida.

The principal results of experimental research during this period can be summarized as follows:

Provenance Comparison Trials. Provenance trials were conducted in several countries, including Senegal, Burkina Faso, and Zimbabwe. The largest of these trials, one being installed by IRBET/CTFT in Burkina Faso (Bonkoungou et al. 1988) and the other set up by the Forestry Research of Zimbabwe (Sniezko and Stewart 1989), were composed of more than 30 provenances each.

These trials showed extreme variability in terms of growth between as well as within provenances. In each region, the local provenances of that region gave the best results. Thus, in West Africa, the West African provenances performed better than those of southern Africa; in southern Africa, the provenances harvested locally gave better results than those from West Africa.

Vegetative Propagation trials. Vegetative propagation trials gave positive results for macro-cuttings planted under glass panels as well as for micro-propagation by in vitro culture; similar field trials, however, have not been fully evaluated.

Research on Symbiotic Systems. Rhizobium, endomycorrhiza, or both simultaneously as a double inoculation gave very encouraging results in the laboratory and in the nursery in Burkina Faso and Senegal. Field trials have been recently installed and cannot be presently evaluated.

Progeny trials. Provenance comparison trials were recently supplemented by progeny trials to study germplasm. Isoenzymatic analyses by electro-phoresis, which will supplement results of the provenance comparison trials, are being carried out by Joly (1992) in France.

Vandenbeldt (1991, personal communication) has proposed a new hypothesis that suggests that higher levels of fertility found at the bases of A. albida are not caused by the tree; rather, the preexistence of good microsites favored the establishment of the tree. This hypothesis, if verified, will have serious implications for research and development.

Thoughts for the Future

The assessment of past experience has led to the following observations:

•  Research on A. albida was essentially devoted to technical aspects and not enough to socioeconomic problems.

The initial direction taken in studying the impact of human geography (Pélissier 1966) on agrarian civilizations of Cayor and Casamance was lost in subsequent studies, which focused solely on the tree rather than the people and their use of the tree.

Socioeconomic studies are needed to account for the highly variable behavior of populations visa-vis A. albida. Montagne (1984) gave the following example of two villages in Niger. In the Dallol Maouri, A. albida is part of the inheritance which the rural people pass on to their children. In the Dallol Boboye, however, A. albida does not come into play in the division of fields inherited from the father: only the baobab (Adansonia digitata) is taken into account. Thus it is evident that the peo-ple of these two villages will not respond similarly to an A. albida regeneration project. The presence of A. albida to relic stands may not reflect the local attitude towards the species. Some stands of the tree were in fact relic stands without any connection with the people, who do not know or feel the need to ensure their regeneration.

Future programs that focus on A. albida should give particular attention to socioeconomic considerations.

• Technical research should, in pursuing stock improvement, integrate more genetic and symbiotic aspects, since the infectivity and the effectiveness of certain microorganism strains vary considerably, both between trees of different provenances and between progenies of the same provenance.

  More research effort should be devoted to mature trees. Most development projects have emphasized regeneration by planting or by protecting natural regeneration. These efforts deserve to be supplemented by work on the management of mature trees. Part of this approach would involve testing different types and intensities of cuts during different times of the year in order to determine optimum pod and foliage production.

  Phenological studies, which have for too long focused on the reverse phenology of A. albida, need to be expanded to include studies on biology of reproduction (allogamy/autogamy, controlled pollination, etc.). Lastly, there remains the question of whether the species belongs to the genus Acacia or to the monospecific genus Faidherbia.

• The new hypothesis according to which the higher level of fertility at the base of the species is caused not by the presence of the tree but rather by the preexistence of microsites favoring the establishment of the tree will have a considerable impact on future action, once it can be verified. Planting strategies will have to bear in mind whether the aim is research or development.

Conclusion

By deciding to emphasize the interaction between forestry and agriculture, the CGIAR is establishing research priorities on systems to which the empirical experience of diverse agrarian civilizations of Sud-ano-Sahelian Africa can contribute.

Besides presenting the important sociocultural and economic relationships that exist between A. albida and man, the previous discussion outlines the results of principal interventions of the past and present and suggests a number of options for future efforts, which must involve partners of national and international research institutions.

The International Centre for Research in Agro-forestry (ICRAF), which has recently been vested with the responsbility for research in agroforestry within the CGIAR, will play a major role in future research on A. albida. Research on this species has already been integrated into the activities of several ICRAF networks of collaborative programs in Africa.

References

Bonkoungou, G.E. 1985. Acacia albida Del., a multipurpose tree for arid and semi-arid zones. FAO Forestry Genetic Resources Information 13:30-36.

Bonkoungou, G.E. 1987. Monographie de Acacia albida Del., espèce agroforestière à usages multiples. Ouagadougou, Burkina Faso: Institut de recherche en biologie et écologie tropicale/Paris, France: Centre national de la recherche scientifique et technologique. 92pp.

Bonkoungou, G.E., Ouédraogo, S., Dianda, M., and Billand, A. 1988. Acacia albida Del. en agroforesterie: stratégie d'amélioration du matériel végétal. Presented at the Journeés scientifiques universitaires, Ouagadougou, Burkina Faso, 31 May-4 Jun 1988. Ouagadougou, Burkina Faso: Centre national de la recherche scientifique technologique. 22 pp.

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CTFT (Centre technique forestier tropical). 1988. Faidherbia albida (Del.) A. Chev. (Synonyme Acacia albida Del.). Nogent-sur-Marne, France: CTFT. 72 pp.

Dancette, C., and, Poulain, J.F. 1968. Influence de l'Acacia albida sur les facteurs pédoclimatiques et les rendements des cultures. IRAT/CNRA Nouvelle contribution. Paris, France: Institut de recherches agronomiques tropicales et des cultures vivrières/Centre national de recherches agronomiques. 45 pp.

Felker, P. 1978. State of the art: Acacia albida as a complementary permanent intercrop with annual crops. Grant no. AID/afr-C-1361. Washington, D.C., United States Agency for International Development. Ph.D. thesis, University of California, Riverside, California, USA. 133 pp.

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Joly, H. 1992. The genetics of Acacia albida (syn. Faidherbia albida). These proceedings.

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Montagne, P. 1984. Faidherbia albida: son développement au Niger. Aix-en-Provence, France: Bois de Feu. 90 pp.

Pélissier, P. 1966. Les paysans du Sénégal. Les civilisations agraires du Cayor aà la Casamance. Saint-Yriex, France: Imprimerie Fabrègue. 939 pp.

Pélissier, P. 1980. Larbre dans les paysages agraires de l'Afrique noire. L'arbre en Afrique tropicale: La fonction et le signe. Cahiers ORSTOM, Série Sciences Humaines 17(3-4):130-136.

Savonnet, G. 1959. Un système de culture perfectionné pratiqué par les Bwaba-Bobo-Oulé de la région de Houndé (Haute-Volta). Bulletin IFAN 21B(3-4):425-458.

Sniezko, R.A., and Stewart, H.T.L. 1989. Range-wide provenance variation in growth and nutrition of Acacia albida seedlings propagated in Zimbabwe. Forest Ecology and Management 27:179-197.

Footnote__________

1. International Centre for Research in Agroforestry (ICRAF), OAU/SAPORAD, B.P. 1783, Ouagadougou, Burkina Faso.

Bonkoungou, E.G. 1992. Sociocultural and economic functions of Acacia albida in West Africa. Pages 1-6 in Faidherbia albida in the West African semi-arid tropics: proceedings of a workshop, 22-26 Apr 1991, Niamey, Niger (Vandenbeldt, R.J., ed.). Patancheru, A.P. 502 324, India: International Crops Research Institute for the Semi-Arid Tropics; and Nairobi, Kenya: International Centre for Research in Agroforestry.